Adjustable stairs



1952 c. E. WEBB, SR, ETAL 3,5331

ADJUSTABLE STAIRS 2 Sheets-Sheet 1 Filed July 18, 1960 S m m m m CLEITUS E-WEBB SR. GLEITUS E.WEBB JR. RBER J WEBB Aug. 28, 1962 c. E. WEBB, SR, Ema 393,2

ADJUSTABLE STAIRS Filed July 18, 1960 2 Sheets-Sheet 2 INVENTORS CLEITUS E.WEBB SR. CLEITUS E.WEBB JR.

ROBERT J. WEBB ATTORNEYS 3,951,261 ADJUSTABLE STAIRS Cleitus E. Webb, Sin, Memphis, Tenn, and (Ileitus E.

Webb, In, and Robert J. Webb, Little Rock, Arie, assignors to Wel-Bilt Products Company, Memphis, Tenn, :2 ctr-partnership Filed July 18, 196i Ser. No. 43,346 1 flaiin. ((31. 182--78) The present invention relates to a stairway and refers more specifically to a foldable, disappearing stairway having improved counter-balancing means.

Foldable, disappearing stairways are particularly desirable in the smaller homes being built today since with such stairways space is not required for permanent stairs leading to little used spaces such as attics. In addition, foldable stairways are much less dangerous in use than vertical ladders, stepladders, and the like normally used for access to attics and similar spaces. Another desirable use of the folding, disappearing stairway is to isolate a space such as an attic, study, or storeroom from other portions of a building.

Prior foldable, disappearing Stairways have, however, had disadvantages which often outweighed the advantages thereof so that the use of the foldable, disappearing stairway has been limited. In particular, many prior disappearing stairways have not been properly counterbalanced so that they are difficult to open or tend to open with such force that injury could result therefrom. In addition, most of the previous foldable, disappearing stairways have been complicated, relatively unreliable and expensive.

It is, therefore, one of the purposes of the present invention to provide a foldable, disappearing stairway including improved reliable counterbalancing means.

Another object of the present invention is to provide a, foldable, disappearing stairway having separate counterbalancing means for each section thereof.

Another object is to provide primary counterbalancing means for a foldable, disappearing stairway which stairway includes a main stairway section adapted to be supported in an open postion by means of a foldable strut extending between the main stairway section and a frame from which the main stairway section is pivoted, comprising a lever secured to the foldable strut and spring means secured at one end to said frame and at the other end to said lever.

Another object is to provide primary counterbalancing means for a foldable, disappearing stairway, as set forth above, wherein said lever extends substantially perpendicularly to the arm of the foldable strut to which it is secured and wherein the lever is provided with S6- lectable means for securing the end of the spring thereto whereby the amount of counterbalancing action provided by the spring may be adjusted.

Another object is to provide primary counterbalancing means for a foldable, disappearing stairway, as set forth above, wherein cam means are provided associated with the end of the arm of the foldable strut to which the lever is connected which cam means is operable to cam said spring into proper position with respect to the arm of said foldable strut to which the lever is secured during movement of the main stairway section.

Another object is to provide secondary counterbalancing means for a foldable, disappearing stairway wherein a pair of connecting links are provided on each side of the main stairway and sub-stairway section in parallel with the main stairway section into an extended and a folded position thereof comprising springs secured between each of said connecting links and one of said stairway sections.

, Another purpose is to provide a foldable, disappearand ing stairway including improved counter'balancing means which is simple in construction, economical to manufacture, and efiicient in use.

Other objects and features of the invention will become apparent as the description of the invention proceeds especially when the description is taken in conjunction with the accompanying drawings illustrating a preferred embodiment of the invention wherein:

FIG. 1 is a perspective view of the foldable, disappearing stairway of the invention including the improved counterbalancing means, and illustrating the main stairway section in the in use position and the sub-stairway section in the extended position.

FIG. 2 is a partly broken away elevational view of the stairway illustrated in FIG. 1 showing the main stairway section in the stored position and the sub-stairway section in the folded position.

FIG. 3 is a partly broken away elevational view of the stairway illustrated in FIG. 1 showing the main stairway section in the in use position and the sub-stairway section in the folded position.

FIG. 4 is a partially broken away end View of the stairway illustrated in FIG. 1 taken in the direction of arrow 4 in FIG. 2.

FIG. 5 is a partial top view of the stairway illustrated in FIG. 1 taken in the direction of arrow 5 in FIG. 2.

FIG. 6 is an enlarged perspective view of the connection of the counterbalancing spring to the foldable strut with the main stairway section in an in use position.

With particular reference to the figures, a specific embodiment of the present invention will now be disclosed.

The foldable and disappearing stairway generally indicated 10 illustrated in FIG. 1 comprises a main stairway section 12, and a sub-stairway section 14 connected to the main stairway section 12 by means of a pair of connecting links 16 and 18 at each side of the stairway sections. The main stairway section 12 is pivoted to one end of a frame 20 which may be set in a ceiling or similar structure 22 by means of straps 48 and is supported from frame 20 in the in use position of the main stairway section by means of foldable struts 26 at each side thereof in conjunction with straps 24.

According to the invention, the foldable and disappearing stairway 19 furtther includes primary counterbalancing means generally indicated 28 at each side of the main stairway section. Secondary counterbalancing means 30 and 32 are also provided in conjunction with each of the connecting links 16 and 18.

In operation, as will be understood, the foldable, disappearing stairway 10 of the invention may be pivoted from tht position illustrated in FIG. 2 into that illustrated in FIG. 3 wherein the main stairway section 12 is in the in use position. The sub-stairway section 14 may then be pivoted on connecting links 1 6 and 18 into the extended position thereof as shown in FIG. 1 whereby the stairway is ready for use.

When it is desired to store the stairway, the reverse procedure is used. It will be understood that the counterbalancing means permits movement of both of the sections of the stairway shown into or out of either position thereof with a minimum of effort.

More specifically, the main stairway section '12 comprises side rails 34 having stairway treads 38 positioned therebetween. A closure 41? for the frame opening 20 is secured to one side of the main stairway section 12 as shown best in FIG. 1. Attached to the side rails 34- are handrails 4-2.

The main stairway section 12 is provided at the end 46 thereof with straps 48 secured to each of the side rails 34, as best shown in FIGS. 2-4. Straps 48 are secured by means of pivot pins 59 and brackets 52 to the frame 20 at one end thereof, as shown in FIG. 4.

Main stairway section 12 thus is pivo-tally supported on the frame for swinging movement in a vertical plane into a stored position wherein the main stairway section is in substantially the same plane as the frame 20, as shown in FIG. 2, and an in use position wherein the main stairway section 12 makes a substantial angle with respect to the frame 20, as shown in FIG. 1.

Foldable struts 26 are provided at each side of the main stairway section as. previously indicated and include a pair of arms 54 and 56 pivotally connected at one end thereof as illustrated at 58. The arms 54 and 56 have their other ends pivotally connected by means of brackets 60 and 64 to the side rails of the main stairway section and to the frame 20 respectively, as shown.

The foldable stIuts 26 in conjunction with the pivot straps 48, serve to support the foldable, disappearing stairway. Straps 48 and struts 26 are further aided in supporting the main stairway section by the primary counterbalancing means 28 which will be considered subsequently.

The sub-stairway section 14 comprises side rails 62 having stair treads 66 secured therebetween, as shown best in FIG. 1. The sub-stairway section 14 is adapted to form an extension of the main stairway section 12, as shown in FIG. 1, when it is in the extended position.

The sub-stairway section 14 is secured to the main stairway section 12 by means of connecting links 16 and :18, previously [referred to, which are pivotally connected at one end to the side rails 62 of the sub-stairway section 14 and at the other end to the side rails 34 of the main stairway section.

Thus, the connecting links 16 and 1 8 support the substairway section 14 on the main stairway section 12 for pivotal movement parallel to the main stairway section between a folded position illustrated in FIG. 2 and an extended position illustrated in FIG. 1. Counterbalancing means, to be discussed later, are also provided to aid in the movement of the sub-stairway section 16 between the two positions thereof.

Primary counterbalancing means 28 for the main stairway section 12 is best illustrated in FIGS. 2 and 5. The primary counterbalancing means comprises bracket 52 secured to frame 20, lever 68 rigidly secured to the end of arm 54, which arm is pivoted by means of pivot pin 81 and bracket 60, to the frame 20 as previously indicated, and spring 70 extending between bracket 52 and lever 68. The primary counterbalancing means also includes an extension '72 on the end of arm 54 which has a cam surface 74 thereon operable to guide the spring 70 into position between extension 72, pin '81, and bracket 60 during swinging of the main stairway section 12 into the in use position thereof.

Also, according to the invention, lever 68 is provided with slots 78 in the edge thereof to provide means for connecting spring 70 to the lever 68 in a position such that spring 76' will operate to swing lever 68 about pivot pin 81 with more or less mechanical advantage depending on the length of the lever arm 68 between the slot to which the spring 70 is connected thereto and the arm 54. Thus, eflicient, primary counterbalancing means is provided for the main stairway section which may be simply adjusted to provide a desired amount of counterbalancing.

In further accordance with the invention, secondary counterbalancing means are provided in conjunction with the sub-stairway section 14 to assist in the movement of the sub-stairway section 14 between the folded and extended positions thereof. The secondary counterbalancing means 30 provided at each side of the stairway sections 12 and 14 include springs 80 respectively connected between brackets 84, the stairway sections 12 and 14, and the connecting members '88 secured to the links 16 and 18, as illustrated best in FIGS. 2 and 3.

Springs 30, when thus connected, operate to tend to cause the sub-stairway section 1 6 to remain in either the folded or extended position thereof depending on which position the sub-stairway section has been placed and to permit easy movement of the sub-stairway section 16 between the two limiting positions thereof. Thus, the foldable, disappearing stairway of the invention is completely counterbalanced by means of simple structure which is easily manufactured and efiicient in use.

In overall operation of the foldable, disappearing stairway 10 of the invention, it will be assumed that the stairway is in the position illustrated in FIG. 2 wherein the main stairway section 12 is in the stored position and the sub-stairway section 16 is in the folded position and is desired to move the stairway into the position shown in FIG. 1 where it may be used.

The main stairway section 12 is first pivoted about pivot pins 50 into the in use position, as shown in FIG. by means of grasping a cord 92 secured to cover 40 and illustrated in FIG. 2 and pulling downward thereon.

As the main stairway section 12 swings clockwise into the position shown in FIG. 3, it will be understood that the lever 78 attached to arm 54 likewise swings in a clockwise direction whereby spring is caused to extend to tend to resist the counterclockwise movement of the main stairway section 12. As spring 70 passes the end 72 of the arm 54, it is cammed by means of cam surface 74 into the pocket provided therefor between the end of arm 54, bracket 60, and pivot pin 80.

On further clockwise movement of lever 78, the end of spring 70 reaches a point where the tendency of spring 70 to move lever 78 counterclockwise is substantially zero due to the fact that lever 78 is substantially coaxial with spring 70 at this time. Thus, it will be seen that the counterbalancing action of the primary counterbalancing means 28 is most effective during the swinging period of the main stairway section and does not tend to move the main stairway section from its in use position once the main stairway section has reached the in use position.

With the main stairway section 16 in the position shown in FIG. 3, it is only necessary to grasp the sub-stairway section 12 and to pivot it into the extended position shown in FIG. 1 to complete the stairway.

The secondary counterbalancing means operate during this movement at the sub-stairway section 12 to tend to prevent the pivoting of the sub-stairway section into the extended position. Once the sub-stairway has reached the extended position, the secondary counterbalancing means operates to maintain the sub-stairway section 16 in the extended position due to the springs 30 and 32 being substantially in alignment with the connecting links 16 and 18 at this time, as will be understood from inspection of FIG. 1.

When it is desired to return the stairway 10 to the folded disappeared position thereof, as shown in FIG. 2, it is only necessary to reverse the above indicated operations. In the reverse procedure, it will be understood that the counterbalancing means operate equally as well to assist in the movement of both of the stairway sections.

The drawings and the foregoing specification constitute a description of the improved adjustable stairs in such full, clear, concise and exact terms as to enable any person skilled in the art to practice the invention, the scope of which is indicated by the appended claim.

What we claim as our invention is:

A disappearing stairway construction comprising a frame constructed around an opening in a ceiling or the like, a main stairway section, pivot means for attachment of one end of the main stairway section to said frame for swinging movement of said main stairway section between a stored position wherein the main stairway section is substantially in the same plane as the frame and an in use position wherein said main stairway section extends at a substantial angle to said frame, a foldable strut at each side of said main stairway section having one end pivotal- 1y secured to the main stairway section adjacent the other end thereof, the struts being folded When said main stairway section is in the stored position and being operable in an unfolded position in conjunction with said pivot means to support said main stairway section from said frame in the in use position of said main stairway section, and counterbalancing means for said main stairway section comprising pivot pins secured to opposite sides of said frame, on ofiset bracket rigidly attached to the other end of each of the foldable struts and positioned between said frame and the other end of said toldable struts, said other end of said foldable struts and the offset brackets being pivotally mounted on the respective pivot pins and forrning an open pocket therewith at the other end of each of the foldable struts, a lever secured to said other end of each of the foldable struts extending substantially perpendicularly thereto adjacent said pocket, a pair of springs one end of each of which is adjustably connected to one of the levers and the other end of which is connected to said frame, a camming surface on the other end of each of said struts for camming the springs into the pockets on the ends of the struts on movement of said main stairway section into an in use position from the stored position thereof whereby said springs are bent around the pivot pins with the main stairway section in the in use position so that the ends of each of said springs are substantially aligned through the respective pivot pins with the main stairway section in the in use position reducing the tendency of the springs to return the main stairway section to the stored position thereof.

References Qited in the file of this patent UNITED STATES PATENTS 1,870,603 Cicilioni Aug. 9, 1932 2,572,281 Pierce Oct. 23, 1951 2,852,176 Harmon Sept. 16, 1958 

